Virtual local area network well-known port routing mechanism for mult--emulators in an open system environment

Abstract

A local host data processing system operating under the control of a local host operating system includes components of multiple emulating hosted operating systems. The host operating system further include a TCP/IP network protocol stack which couples to the communications facilities of the host system connected to a local area network for communicating with a number of remote host systems. Host and hosted operating systems share the same TCP/IP network protocol stack. A virtual network mechanism is configured within the local host system to be operatively coupled to the host network protocol stack and provide access to well-known port application programs. When so configured, the mechanism functions as another LAN to which multiple virtual host systems are attached for executing applications under control of the emulating hosted operating systems. The mechanism transforms the well-known port identifier of each inbound packet into a non-well-known port identifier in addition to other station address identifier fields. It then redirects the transformed packet back to the IP layer of the stack for transfer to the appropriate well-known port application program being run by the hosted operating system of the particular virtual host system. The mechanism reverses this operation for each reply packet which it redirects back to the IP layer for forwarding to the remote system. This eliminates the need to specify additional protocol stacks and to provide additional communication hardware facilities for handling multiple instances of well-known port applications programs running on the different virtual host/multiple hosted operating systems.

Claims

1. A method which allows a local host system to share a network software facility of the local host system operating system between a number of application servers operating under the host operating system and a corresponding number of application servers operating under components of a plurality of hosted operating systems running under control of the local host operating system, the local host system being coupled to at least one remote host system through a local area network (LAN) and an internetwork, the network software facility being coupled to a network interface unit which includes interfacing hardware and software for connecting the local host system to the LAN for communicating with the remote host system using a standard communications network protocol which is characterized by assigning different station address identifier values to each host system and well-known services function identifier values to the different data communications application servers associated with local host system and hosted operating systems so that servers performing the same service function are assigned the same well-known services function identifier value for directing incoming packets sent by the remote host system to the appropriate application server, said method comprising the steps of:

(a) configuring a virtual network mechanism within the local host operating system to be operatively coupled to the host operating system network software facility through a plurality of network interface structures to function as a virtual LAN connected to a plurality of virtual host systems running the hosted operating system with each virtual host system operating as if it contained its own network software facility;

(b) preallocating memory and initializing a different set of structures in preallocated memory for each of the plurality of virtual host systems which operate in conjunction with the virtual network mechanism and the plurality of hosted operating systems, each different set of structures containing a unique unit number identifying the virtual host systems associated therewith and a unique IP address designating the particular virtual host system within the virtual LAN;

(c) mapping predetermined portions of each incoming packet by the virtual network mechanism sent by the remote host system and received from the local host communications network software facility by changing the station address identifier value of each incoming packet to specify the local host system as a destination and the particular virtual host system as a source of the packet for returning any reply packet and changing the well-known services identifier value to a virtual host identifier value so that the packet received from the virtual network mechanism is directed by the network software facility to the appropriate application server of the designated one of the plurality of hosted operating system for processing; and,

(d) remapping the predetermined portions of each outgoing reply packet sent by a hosted system application server through the network software facility to the particular virtual host system by restoring the remote host station address identifier and well-known service identifier values so each outgoing reply packet sent by the virtual network mechanism to the internetwork appears to the remote host system as a reply packet to the communication between the remote host system and the hosted system application server as if the server had been reached through the LAN using the originally sent station address assigned to the particular hosted operating system with the well-known services identifier value.

2. The method of claim 1 wherein the virtual network mechanism includes interfacing software similar to the network interface unit and a common set of software routines utilized by each of the plurality of virtual host systems.

3. The method of claim 2 wherein the network software facility includes a TCP/IP protocol stack containing TCP and IP layers and the virtual network mechanism utilizes the network routing capabilities of the IP layer.

4. The method of claim 1 wherein the standard communications network protocol is the TCP/IP protocol, the station address identifier value corresponds to an IP address containing IP source and IP destination addresses and the well-known service function identifier value corresponds to a TCP well-known port number value containing TCP source and TCP destination port numbers.

5. The method of claim 1 wherein configuring step (a) of the method includes the step of:

(d) loading and initializing each of the plurality of hosted operating systems using a number of directives.

6. The method of claim 1 wherein each different set of structures includes predetermined types of control data structures including a first structure which defines the existence of the particular virtual host system to the network software facility and a second structure which defines the virtual host system.

7. The method of claim 6 wherein the first structure includes a plurality of fields, a first field containing a name which identifies the virtual host system and a second field designating the second structure associated with the virtual host system.

8. The method of claim 6 wherein the first structure is an interface network structure utilized by the host operating system and the second structure is a software control structure which is used to manage packet processing for each of the client application programs running on the remote host system accessing application services running on that particular virtual host system.

9. The method of claim 7 wherein the predetermined types of control data structures includes a number of client table structures, each client table structure being associated with a different client application program of the remote host system which has established communication with a particular virtual host system.

10. The method of claim 9 wherein a new client table is assigned by the particular virtual host system each time a connection packet is sent by a different client application program running on the remote host system.

11. The method of claim 10 wherein the remote host system establishes connection with the hosted operating system data communication services application servers of the plurality of virtual host systems by configuring the remote host to have the local host system function as a "gateway" so that the local host system communications network software facility automatically routes incoming packets sent by the remote host system to designated ones of the virtual host systems.

12. The method of claim 10 wherein the client table of each set of structures includes a predetermined number of fields, a first field for storing the station address identifier value of the remote system client application program, a second field defining the operational state of the client table, third and fourth fields for defining different client application program port identifier values and a fitch field for storing a timer count value defining client application program activity.

13. The method of claim 8 wherein the second structure contains a predetermined number of fields, a first field designating the name of the virtual host system, a second field for storing the state of the virtual host system, a third field for maintaining a count of the number of different client entries being managed by the virtual network mechanism, fourth and fifth fields for storing the common local host and unique virtual host station address identifier values respectively and a sixth field for storing a client pointer value for accessing the first client table structure generated by the virtual host system.

14. The method of claim 13 wherein the virtual host station value for a first one of the virtual host systems is generated by performing an arithmetic operation on the common local host station address identifier value.

15. The method of claim 1 wherein each virtual host system is used to process packets transmitted utilizing one of a number of protocols defining a predetermined type of standard protocol.

16. The method of claim 1 wherein the method further includes the step of:

(f) saving the station address identifier value of the remote host system and the well-known services identifier value contained in each incoming packet in a client table structure generated by the particular virtual host system which can be indexed through the virtual identifier in response to having received an initial connection packet from a client application program running on the remote host system for enabling the subsequent mapping of each reply packet.

17. The method of claim 1 wherein the mapping step (a) of the method includes the step of mapping the well-known services identifier value to a non-well-known services identifier value containing the well-known services identifier value.

18. A virtual network mechanism which allows a local host system to share a network software facility of the local host system operating system between a number of data communications application servers operating under the host operating system and a corresponding number of application servers operating under components of a plurality of hosted operating systems running under control of the local host operating system, the local host system being coupled to at least one remote host system through a local area network (LAIN) and an internetwork, the network software facility being coupled to a network interface unit which includes interfacing hardware and software for connecting the local host system to the LAN for communicating with the remote host system using a standard communications network protocol which is characterized by assigning different station address identifier values to each host system such that the local host system and hosted operating systems are assigned different station addresses and well-known services function identifier values to the different data communications application servers associated with local host system and each of the plurality of hosted operating systems so that servers performing the same service function are assigned the same well-known services function identifier value for directing incoming communication data packets sent by the remote host system to the appropriate communications application server running on the particular hosted operating system, said mechanism comprising:

(a) an interface component configured within the local host operating system to operatively couple the virtual network mechanism to the host operating system communications network software facility as a virtual LAN connected to a plurality of virtual host systems which are the components of the plurality of hosted operating systems;

(b) an initialization component for preallocating and initializing a different set of structures for each of the plurality of virtual host systems which operate in conjunction with the virtual network mechanism and the plurality of hosted operating systems, each different set of structures being initialized to contain a unique number value identifying a particular one of the virtual host systems and a unique IP address designating the virtual host system on the virtual LAN;

(c) a first mapping component coupled to the interface component for mapping predetermined portions of each incoming packet sent by the remote host system and received from the interface component through the local host network software facility so that the station address identifier value of each incoming packet is changed to specify the common local host system as a destination and the particular virtual host system as a source of the packet for processing each reply packet and the well-known services identifier value is changed to a virtual identifier value so that the packet received from the virtual network mechanism is directed by the network software facility to the appropriate application server of the designated hosted operating system for processing; and,

(d) a second mapping component for mapping the predetermined portions of each outgoing reply packet sent by a hosted system communications application server through the network software facility to the interface component by restoring the remote host station address identifier and well-known service identifier values so each outgoing reply packet sent by the virtual network mechanism to the internetwork appears to the remote host system as a reply packet to the communication initiated by a client application program running on the remote host system and the hosted system application server as if the server had been accessed through the LAN using the originally sent station address assigned to the particular hosted operating system by the well-known services identifier value.

19. The mechanism of claim 18 wherein each set of control structures includes a first structure which defines the existence of the virtual host system to the network software facility and a second structure which defines the virtual host system operational status.

20. The mechanism of claim 19 wherein the first structure is an interface network structure utilized by the host operating system to communicate with the virtual host system network facility and the second structure is a software control structure which the virtual host system uses to manage packet processing for each of the client application programs running on the remote host system., the software control structure containing a predetermined number of fields, a first field designating the name of the virtual host system, a second field for storing the state of the virtual host system, a third field for maintaining a count of the number of different client entries being managed by the virtual network mechanism, fourth and fifth fields for storing the common local host and unique virtual host station address identifier values respectively and a sixth field for storing a client pointer value for accessing the first client table structure generated by the virtual host system.